The Harriet Pipelines are transmission pipelines located in north-west Western Australia. The pipelines are owned under three joint ventures. Quadrant Energy has the largest interest in these joint ventures, with Santos acting as a substantial minority partner.  Quadrant Energy operates the pipelines and the associated Varanus Island.

Both pipelines associated with the Harriet Pipelines are 100 km in length and have a capacity of 300 TJ/day. Varanus Island is surrounded by network of fixed production platforms which feed gas, oil and condensate into the Island's facilities for processing. Key facilities include those that support the Quadrant Energy-operated John Brooks, Harriet and East Spar Joint Ventures. The Harriet Pipelines then transport the natural gas into the Dampier to Bunbury Natural Gas Pipeline (DBNGP) and the Goldfields Gas Pipeline (GGP).

The Harriet Pipelines are currently non-scheme pipelines, and are subject to the access regime for non-scheme pipelines under Chapter 6A of the NGL and Part 23 of the NGR.